I have gone through two sets of Heidenaus and each rear was squared off to the point where I changed them out after about 16,000 kms (10,000 miles). The fronts were still in good shape and I could probably have run two rears for each front, but I am conservative and changed out both front and rear at the same time. I am now running Mitas E-07 Dakars and have no noticeable squaring off of the rear after 12,000 kms. The rear Mitas is narrower than the Heidenau and, of course, the sidewall on the Mitas Dakar is a lot more rigid. The Mitas has performed well on and off road, wet or dry, although nothing works well in the mud! Cheers, David